Monte Carlo simulation framework for assessing heavy metal exposure and adverse health effects in fly-in fly-out workers

Heavy metals (HMs) are persistent, non-biodegradable pollutants in airborne particulate matter (PM) that pose serious health risks. Fly-in fly-out (FIFO) workers, exposed to prolonged pollution, are especially at risk, yet their health risks remain underexplored. This study develops a framework to assess HMs exposure and health risks in FIFO workers. Over 12 months, samples of six HMs (Fe, Zn, Cd, As, Ni, Pb), were collected from indoor and outdoor environments at a major FIFO worksite in Bushehr, Iran. health risks, including cancer and other diseases, were estimated using Monte Carlo simulation. FIFO workers faced 21.42 % higher health risks than drivein drive-out (DIDO) workers, with Pb (0.11 f 0.194 mu g/m3) as the most significant factor, showing a hazard quotient (HQ) of 2.88 and cancer risk (CR) of 1.28E-05. Indoor FIFO workers had 11 % lower health risks than outdoor workers, primarily due to reduced exposure to As (0.03 f 0.02 mu g/m3), strongly linked to cancer, with HQ of 7.89 and CR of 5.04E-04. Ni (0.027 f 0.036 mu g/m3) was the main contributor to non-cancerous hazards, with HQ of 26.1 and CR of 6.50E-05, while Cd (0.005 f 0.004 mu g/m3) showed a significant risk difference, with HQ of 3.70 and CR of 4.91E-05. Conversely, Fe (8.93 f 5.49 mu g/m3) and Zn (0.1 f 0.19 mu g/m3) were associated with the lowest non-cancer hazards (HQ 7.08E-04 and 1.05). Additionally, FIFO workers in open environments faced 16.35 % higher risks than those in enclosed spaces, peaking at 19.79 %. overall, FIFO workers have higher health risks than DIDO workers. Improving ventilation, prioritizing indoor work, and Shortening exposure reduce these risks.